COMPARISON OF REMIFENTANIL AND PROPOFOL INFUSIONS FOR SEDATION DURINGREGIONAL ANESTHESIA

Background and Objectives. Patients treated with regional anesthesia o ften require concomitant medication for comfort and sedation. Propofol is widely used for this purpose. Remifentanil, a new ultra-short-acti ng opioid, exhibits at low doses distinct sedative properties that may he useful for supplementation of regional anesthesia This study compa red the effectiveness of remifentanil and propofol infusions for provi ding sedation during regional block placement and surgery. Methods. In an open, prospective trial, 28 patients were randomly allocated to re ceive continuous infusions of remifentanil (6 mu g/kg/h) or propofol ( 3 mg/kg/h) for sedation during spinal or axillary regional anesthesia. Infusion rates were titrated to maintain a sedation level greater tha n or equal to 2 as assessed with the Observer's Assessment of Alertnes s Scale, Vital signs were measured continuously, during and for 2 hour s after ending study drug infusion. Results. Similar scores for comfor t and sedation were obtained in both groups during placement of the re gional block and during surgery. Degree of sedation correlated with dr ug infusion rate of remifentanil (P <.002) but not for propofol. Respi ratory rate decreased in the remifentanil group in absence of surgery (P <.05), Mean arterial pressure and heart rate were 20% lower in the propofol group (P <.05). Return to alertness occurred after 10 +/- 6 m inutes in the remifentanil group and after 16 +/- 15 minutes in the pr opofol group. Similar incidences of hypotension, bradycardia, and naus ea and vomiting were found in both groups, but intraoperative respirat ory depression and nausea were more prominent in the remifentanil grou p. Conclusions. When titrated to the same sedation level, remifentanil provided a smoother hemodynamic profile than propofol during regional anesthesia. The frequent occurrence of remifentanil-induced respirato ry depression requires cautious administration of this agent. The inci dence of adverse reactions seen with both agents during and after thei r administration makes the management of such sedative infusion techni ques difficult.